The intensive care unit (ICU) is characterized by a plethora of noise resulting from alarms, doors slamming, people talking, employees pushing meal carts, and many other distractions. The main sources of alarms are infusion pumps, mechanical ventilators, intra-aortic balloon pumps, and patient monitors. False alarms, a large number of alarms, and overly loud alarms all contribute to alarm fatigue in medical staff. Alarm fatigue corresponds to reduced response to valid alarms, increased stress levels, hearing loss, and fatigue. In addition, alarm fatigue can cause medical staff to permanently turn off alarms or set their triggering parameters outside of realistic ranges.
Current alarms, due to their frequency and poor positive predictive value (PPV), cause alarm fatigue for clinicians. Alarms in the operating room (OR) sound frequently but in 85-99% of cases do not require clinical intervention. Alarms have a PPV of ˜27%, and many ‘true’ alarms are clinically insignificant. Thus, clinicians distrust alarms, losing confidence in their significance. As alarm frequency increases, clinicians develop ‘alarm fatigue’ resulting in desensitization, missed alarms, and delayed responses. Alarm fatigue can cause clinicians to set alarm parameters outside effective ranges to decrease alarm occurrence, decrease alarm volumes to inaudible levels, reflexively silence frequently insignificant alarms, and be unable to distinguish alarm urgency. Yet, when a ‘true alarm’ that requires clinical intervention is ignored or inadvertently missed, patient harm can result. Decreasing the incidence of false alarms will require improvements in sensors and processing algorithms. Even with optimal activation, there will always be false and uninformative alarms (e.g., apnea alarm when the patient is being intubated), the need for reliable response to true alarms signifying actionable situations, as well as the need to reduce noise in clinical settings.
The Occupational Safety and Health Administration (OSHA) has set legal limits on occupational noise exposure—e.g., no more than 8 hours of 90 dB exposure with the exposure time halving for every increase of 5 dB (e.g., ≦4 hours if 95 dB). For reference, a jackhammer at 15 meters yields 95 dB while a vital signs monitor with a QRS volume setting of 2 located 3 feet from an anesthesia provider at the head of the OR bed yields 80 dB. In the OR, the latter noise adds on top of the ventilator, surgical sounds (e.g., orthopedics drill, suction, clanging instruments), intercom, conversations, and other alarms. Since every manufacturer believes that their device's ‘emergency condition’ is most important, the accumulating sound creates a vicious positive feedback loop that may be detrimental to patient safety and practitioner well-being. As a result, clinicians and patients are subjected to noise levels that far exceed OSHA recommendations.
Being exposed to up to 700 alarms per day in most acute care settings produces alarm fatigue and may precipitate hearing loss. While the World Health Organization recommends that noise levels be <30 dB at night in hospitals, current levels are closer to 60 dB. For healthcare providers, excessive noise causes miscommunication, inattention, loss of concentration, memory impairment, headaches, burnout, fatigue, and impaired task performance. These outcomes not only lead to clinician dissatisfaction but also have negative consequences on their ability to provide high quality patient care.
For ICU patients, excessive noise and alarm fatigue can affect sleep, wound healing, mental state, and immune function that may lead to increased blood pressure, hemodynamic instability, increased sedation requirements, loss of sleep, and delirium. More importantly, noise in the ICU can result in post-traumatic stress disorder (PTSD) for patients.
The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-V), defines PTSD as a potentially debilitating psychiatric condition, which develops as the result of being exposed to a traumatic event or events, and characterizes PTSD by symptoms in three domains: 1) symptoms of re-experiencing such as intrusive thoughts, 2) symptoms of avoidance and emotional numbing, and 3) symptoms of increased arousal. Furthermore, these symptoms must meet two criteria to satisfy the diagnostic criteria: 1) they must cause significant impairment in social, occupational, or other important functional domains, and 2) they must be present for at least one month after exposure to the traumatic event or events. Studies reported in previous literature describe a wide range of PTSD prevalence in the ICU, ranging from 5%-63%. Yet to this date it has never been studied whether noise in the ICU is an independent predictor for PTSD.
There is, however, recent data that demonstrates PTSD symptoms in ICU patients. A study conducted on 382 patients at the BRAIN-ICU at Vanderbilt showed that at 12 months post ICU discharge 7% of patients had PTSD. However, it is important to point out that these patients had a 15% incidence of intrusion, a 43% incidence of avoidance, and a 46% incidence of hyperarousal symptoms; yet unless all three symptoms were present together, a formal PTSD diagnosis could not be made even though having just one of these PTSD symptoms can significantly affect one's quality of life.
Furthermore, there is research to indicate that these symptoms are elicited by noise from alarms. Research shows that patients with delusional memories are more likely to develop PTSD symptoms than patients with factual memories. Periods of delirium with associated delusions may predispose patients to PTSD. On the other hand, periods of alertness, which permit the organization of factual memories, may serve as a protective role and prevent the development of PTSD-related symptoms after discharge. However, periods of alertness cannot occur if the patient has excessive daytime sleepiness from poor sleep in the ICU due to alarm and non-alarm noise.
Alarms that interfere with sleep may also weaken the immune system by decreasing lymphocyte production. The Food & Drug Administration's Maude database contains numerous voluntary reports of alarm-related injuries including 216 deaths over 5 years (2005-10); this likely significantly underestimates the incidence of alarm-related harm.
There is a recent national focus on alarm management and patient safety. The Joint Commission's (TJC) recent attention on alarms exemplifies societal concern about this issue. TJC declared alarm management and safety to be one of their 2014 National Patient Safety Goals. They now require hospitals to prioritize alarm management and to assess the appropriateness and priority of every alarm in their hospital. The Emergency Care Research Institute (ECRI) identified alarm hazards as number one of the “Top 10 Health Technology Hazards” in 2013. They specifically cited turning down alarm volumes to inaudible levels as a major safety issue. The mission of a 2011 Association for the Advancement of Medical Instrumentation (AAMI)-FDA summit on alarms was “by 2017, no patient will be harmed by adverse alarm events.”